Tuesday, May 01, 2007

Nature Loves a Vacuum

A new device placed in say, Iceland, could suck up atmospheric carbon dioxide emitted from vehicles as far away as Tokyo, making it a potentially useful tool in battling ever-rising levels of this greenhouse gas.

....Scientists have proposed many possible ways to reduce the amount of carbon dioxide in the air: emissions could be reduced by using alternative energy sources, such as solar and wind power or alternative fuels, like ethanol or natural gas; and scrubbers could be placed on power plants to remove carbon dioxide and other gases from their exhaust.

But unlike these solutions, which reduce emissions, the new device captures carbon dioxide molecules that are already in the air and releases them as a pure carbon dioxide stream. This stream can be sequestered or used to enhance oil recovery.

“We are trapping carbon dioxide about 1,000 times faster than a tree does,” said study leader Klaus Lackner of Columbia University.

The device has an opening that pulls air in and the carbon dioxide in the air sticks to absorbent compounds (or sorbents) inside the device.

“Once you have the CO2 attached to the sorbent, you have to pry it loose again,” which is the costly part of the procedure, Lackner said.

The scientists who created the device point out one particular advantage: It could be placed wherever sequestered carbon dioxide would be stored, instead of where emissions occur. By contrast, scrubbers are impractical to use on cars, which contribute 20 percent of the global carbon dioxide emissions, and it is difficult to retrofit power plants with the scrubbers.